Friday, April 23, 2010
Ryan Murphy
Chris Blondeau- The director
Chris Blondeau -the diver
Thursday, April 22, 2010
Laura Verhegee
explains the effect of the turbine on the Marine Ecosystems.
Citations
Quotes from leading environmental organisations
David Suzuki Foundation (Vancouver, BC, Canada)
“We were pleased to learn that both BC Hydro and federal agencies are interested in pursuing further demonstration initiatives involving tidal and ocean power technologies. As you know, we believe these forms of energy development are worthy of attention and research and development support. … (We) support the further development of tidal and ocean power sources and encourage inclusion of those sources within government and utility programs designed to foster renewable energy sources.” -- Gerry Scott (Director, Climate Change Campaign) 07/2001
David Suzuki Foundation (Vancouver, BC, Canada)
“BC’s coastline is ideal at several locations for hydro turbine energy production. Please encourage BC Hydro, Environment Canada and Industry Canada to contact our office for material on Climate Change and why tidal energy is one of Canada’s solutions. … Government support for Ballard Power moved it from an undercapitalized energy concept to a world leading fuel cell developer. Government support for ecologically friendly hydro-turbine technology could similarly move the Davis concept into production on a national and international scale.” - Jim Fulton (Executive Director) 07/2001
Sierra Club of British Columbia (Victoria, BC, Canada)
“The Sierra Club of BC is very interested in exploring what means of support the Government of Canada is proposing to offer to renewable energy projects in BC. We are especially interested in exploring how support could be given to prototypes that show a potential for successful pilot projects, such as the Davis Hydro Turbine.”
- Michael Mascall (Chair) 07/2001
The Society Promoting Environmental Conservation (Vancouver, BC, Canada)
“Tidal energy in particular deserves full investigation as a viable energy alternative. Of all the choices at our disposal, tidal energy appears to be the least understood – even though it has many times the energetic potential as wind, for example. The Society Promoting Environmental Conservation fully supports any initiatives or demonstration projects which would prove it to both environmentally benign and a reliable source of electrical power.” - David Cadman (President) 07/2001
Extra Information
http://www.racerocks.com/
http://en.wikipedia.com/wiki/Tidal_power
http://www.cleancurrent.com/
IMPACT of TURBINE ON THE PACIFIC OCEAN
For centuries, tidal devices have been used to harvest energy to meet the needs of various communities. In recent times, with the green revolution concerns over the impact of turbines on oceans has sparked a new debate. In this section of the blog, I will be looking at and evaluating the impact of turbines on marine life.
Tidal energy is a renewable resource that does not result in the emission of pollutants into the atmosphere. Since it does not contribute to acid rain or global warming, tidal energy is thought to be environmentally friendly. When considering installing turbines, the environmental impact on marine life is the overriding issue. The exact impact of this on complex marine ecosystems is not known. Nevertheless, the environmental impacts of tidal energy are expected to be much less than other non-renewable forms of power generation.
Case study
Researchers identified potential problems in the Johnstone Strait, a 110 km channel along the north east coast of Vancouver Island, which is a major migration route for salmon and is home to resident marine mammals notably killer whales. It was uncertain if salmon, which will generally seek out advantageous currents during their migration, would “see”, react and avoid large rotating turbine blades. There was not any particular elevation in the water column which the fish favour over others and which would be used to locate turbines to avoid collision. Researchers concluded that a demonstration unit would provide a much-needed opportunity to assess turbine technology and its environmental effects especially those related to fish and marine mammal impacts. In regards to pollution, since there are no emissions or discharges from these units, marine pollution would be restricted to matters related to leakage of lubricants and the type of paint or coating that the subsurface structures would use to prevent excessive growth of marine organisms. Careful selection of these materials would help to lower the risk of pollution.
The general picture
In this age of growing awareness of the environment and environmental issues, alternative sources of energy have grown increasingly important. The advantages of utilising such energies are given below;
- durability of components
- requires no fuel
- produces no emissions
- produces no waste products during operation
- open sluice, slow-rotor design allows for easy passage of fish and marine invertebrates
- Minimal noise expected during operation
While providing a clean, reliable source of energy, the installation of any artificial device into the environment will affect it in some ways. A number of concerns have been raised about the environmental impacts of wave and tidal devices. Among the most important of these are:
- Impact on fish and marine mammal movement and/or migration rotors
- Deflection of local energy regime (as energy is removed by turbines)
- Marine fouling (encrustation) of energy system components by algae and invertebrates
- Noise and/or electro-magnetic fields (EMFs) in marine environment
Possible solutions and responses to the concerns
- Rotors stop at slack tide, protective barriers, sensory braking tech., acoustical tracking technology to guide fish and mammals
- Energy displacement is NOT expected to be significant
- Use of non-toxic, anti-fouling materials
- Noise and/or EMF from operation expected to be minimal
The environmental impacts of any energy scheme should be considered carefully. Based on my research, I believe that the benefits of using turbines far outweigh any negative consequences because there are viable solutions to the impact of turbines on marine life. Tidal energy is the most attractive option because of the small ecological footprint, predictability and modest environmental impact. In comparison to other sources of energy, tidal technology appears to be the most environmentally friendly option.
This factor must’ve been important in Race Rocks’ decision to install turbines, because as it is under the stewardship of Pearson College, it also subscribes to the same values that define the UWC experience.
Undoubtedly, more research should be funded to gain a greater understanding of the potential effects of tidal devices, form a wide range of sources.
www.bluenergy.com/ pdfsOceanBlueEnergy/TidalEnergyPrimer.pdf
UK PARLIAMENT... Select Committee on Science and Technology Seventh Report
http://www.parliament.the-stationery-office.co.uk/pa/cm200001/cmselect/cmsctech/291/29104.htm
Race Rocks' energy production before the Tidal Turbine
The tidal turbine arrived at Race Rocks only in 2007, before the island had many different sources of energy. At the beginning Great Race Rock was supplied in energy by oil. In 200O the 7 oil tanks that had been brought on the island in the 1970’s were taken off the island and their cement base had been remove to allows grass and vegetation to grow up again. Also, the island mainly depended on Diesel to provide energy to the lighthouse and the few buildings of Great Race Rock. The use of such a fuel is quite damageable for the environment. First of all, there is a high risk for realising fuel into the ocean, especially in a harsh environment such as the coast of the island. Also, the emission of CO2 is quite important according to the Race Rocks official website: “Assuming 50,000L/year marine grade diesel combustion (rough average requirement for CCG lightstations) the diesel system contributes about 133,500 kg/year CO2 emissions (Carbon coefficient for distillate fuel (fuel oil): 161.44 pounds of CO2 per million BTU, or 22.29 pounds per gallon, or 2.67 kg/L. (U.S. Environmental Protection Agency, 1999. U.S. Inventory of Greenhouse Gas Emissions and Sinks: 1990-1997.)) ”.And this is not accounting the transformation process, the transportation and the release of gas in the atmosphere after burning, basically it’s really polluting the environment around it, and as an ecological reserve it’s really not appropriate. Finally, the exhaust of that gas contains several chemical components that we don’t know the effects on the environment yet.
*www.racerocks.com
Alternative Sources of Energy at Race Rocks
Starting in 1997, Lester B. Pearson College had to raise the funds to keep the diesel generators working to supply electricity to Race Rocks . The cost of doing this was originally $11,000 per year and within 4 years reached $20,000. The lighthouse light and foghorn had been made energy self- sufficient with 8 solar panels and a battery array installed by the Coast Guard by 1997. By 1998 proposals to develop support for alternate energy technologies to make the rest of the island energy-self sufficient were underway.
In September 2006, a bi-directional flow turbine was installed at a depth of 20m below the water surface at Race Rocks. There has been a trend in investigating and implementing new, greener sources of energy at Race Rocks, and this is the next step in that process.
Ocean thermal energy conversion (OTEC ) uses the temperature difference that exists between deep and shallow waters to run a heat engine. As with any heat engine, the greatest efficiency and power is produced with the largest temperature difference. Historically, the main technical challenge of OTEC was to generate significant amounts of power efficiently from this very small temperature ratio. Changes in efficiency of heat exchange in modern designs allow performance approaching the theoretical maximum efficiency.
The Earth's oceans are continually heated by the sun and cover nearly 70% of the Earth's surface; this temperature difference contains a vast amount of solar energy, which can potentially be harnessed for human use. If this extraction could be made cost effective on a large scale, it could provide a source of renewable energy needed to deal with energy shortages and other energy problems. The total energy available is one or two orders of magnitude higher than other ocean energy options such as wave power; but the small magnitude of the temperature difference makes energy extraction comparatively difficult and expensive, due to low thermal efficiency. The energy carrier, seawater, is free, though it has an access cost associated with the pumping materials and pump energy costs. However OTEC plants tend to operate at a low overall efficiency thus any thorough cost-benefit analysis should include these factors to provide an accurate assessment of performance, efficiency, operational, construction costs, and returns on investment.
Aquaculture is the most well-known by-product of OTEC. It is widely considered to be one of the most important ways to reduce the financial and energy costs of pumping large volumes of water from the deep ocean. Deep ocean water contains high concentrations of essential nutrients that are depleted in surface waters due to biological consumption. This "artificial upwelling" mimics the natural upwellings that are responsible for fertilizing and supporting the world's largest marine ecosystems, and the largest densities of life on the planet.
Cold-water delicacies, such as salmon and lobster, thrive in the nutrient-rich, deep, seawater from the OTEC process. Microalgae such as Spirulina, a health food supplement, also can be cultivated in the nutrient rich water. Because the OTEC process uses cold, deep-ocean water and warm ocean water from the surface, it can be combined in various ratios to deliver sea water of a specific temperature conducive to maintaining an optimal environment for aquaculture.
Wave Power
Wave power is the transport of energy by ocean surface waves, and the capture of that energy to do useful work — for example for electricity generation, water desalination, or the pumping of water (into reservoirs).
Wave power devices are generally categorized by the method used to capture the energy of the waves. They can also be categorized by location and power take-off system. Method types are point absorber or buoy; surfacing following or attenuator oriented parallel to the direction of wave propagation; terminator, oriented perpendicular to the direction of wave propagation; oscillating water column; and overtopping. Locations are shoreline, near shore and offshore. Types of power take-off include: hydraulic ram, elastomeric hose pump, pump-to-shore, hydroelectric turbine, air turbine, and linear electrical generator. These capture systems use the rise and fall motion of waves to capture energy. Once the wave energy is captured at a wave source, power must be carried to the point of use or to a connection to the electrical grid by transmission power cables.
Here is a description of a wave power system:
An example of a surface following device is the Pelamis Wave Energy Converter. The machine is made up of connected sections which flex and bend as waves pass; it is this motion which is used to generate electricity. The Pelamis is an attenuating wave energy converter designed with survivability at the fore. The Pelamis's long thin shape means it is almost invisible to hydrodynamic forces, namely inertia, drag, and slamming, which in large waves give rise to large loads. Its novel joint configuration is used to induce a tunable cross-coupled resonant response. Control of the restraint applied to the joints allows this resonant response to be ‘turned-up’ in small seas where capture efficiency must be maximised or ‘turned-down’ to limit loads and motions in survival conditions.
The Pelamis device consists of a series of semi-submerged cylindrical sections linked by hinged joints. The wave-induced relative motion of these sections is resisted by hydraulic cylinders which pump high pressure oil through hydraulic motors via smoothing hydraulic accumulators. The hydraulic motors drive electrical generators to produce electricity. Power from all the joints is fed down a single umbilical cable to a junction on the sea bed. Several devices can be connected together and linked to shore through a single seabed cab
Deep water wave power resources are truly enormous, between 1 TW and 10 TW, but it is not practical to capture all of this. The useful worldwide resource has been estimated to be greater than 2 TW. Locations with the most potential for wave power include the western seaboard of Europe, the northern coast of the UK, and the Pacific coastlines of North and South America, Southern Africa, Australia, and New Zealand. The north and south temperate zones have the best sites for capturing wave power. The prevailing westerlies in these zones blow strongest in winter. Waves are very predictable. The waves that are caused by winds can be predicted five days in advance. Tidal currents, caused by lunar positions, are known 100 years in advance. Water has a power density that is 832 times greater than air's power density. That means that large amounts of energy can be obtained from relatively small devices. For example, it would require a wind turbine three times its size to generate the same amount of power as a regular-sized underwater turbine.
Challenges
The device has to efficiently convert wave motion into electricity. Generally speaking, wave power is available at low speed and high force, and the motion of forces is not in a single direction. Most readily-available electric generators operate at higher speeds, and most readily-available turbines require a constant, steady flow.
There is a potential impact on the marine environment. Noise pollution, for example, could have negative impact if not monitored, although the noise and visible impact of each design varies greatly.